The object of this study is the building frames with rigid beam-to-column assemblies. The aim of the study is to assess the impact on the accuracy of the solution of the problem of the error of the input data and the number of given coefficients of the deflection equation. The studies were carried out using analytical and experimental methods of regularization, reduction of measurements, solutions on a measuring compact, polynomial approximation, linear Lagrangian interpolation and numerical differentiation.

Rigid coupling of a beam with a rack is modeled analytically and by a full-scale experiment. For a quantitative assessment of the effectiveness of solving the problem, the values of the target parameter and the optimization criterion are determined through the minimum of the Lebesgue function. It is proposed to use the obtained results of solving the inverse Cauchy problem in experimental and theoretical studies of rack-and-beam structures.

The possibility of generating three different translational surfaces of velarodial type by having the same main frame of the surface is proved and illustrated. Using these three different ruled surfaces as middle surfaces of thin shells allows to extend the number of architectural forms in construction practice.

Static analysis of the shells with the middle surfaces under consideration is performed using the SCAD standard finite element software. The results of the analysis of different ruled shells with oval-shaped base, but of the same main frame, imply that the stress, moment and displacement distributions are almost identical in two of the three shells. Moreover, it is established that the Gaussian curvature of these two shells is negative, and is zero in the third one. Therefore, there is no sense in determining the optimal shell in terms of strength out of the two shells with negative Gaussian curvature. Rather, these two shells may be evaluated based on another criterion, for example, complexity of manufacturing.

Analysis of the research results presented in the scientific and technical literature showed the absence of data about the operation of welded vertical joints of large-panel buildings on embedded parts with connecting elements in the form of bent and rolled angle bars. In order to determine the technical parameters necessary for the calculation and design of large-panel buildings, experimental researches of the operation of welded vertical joints on embedded parts with connecting elements in the form of bent and rolled corners under the action of tensile and shear forces were carried out. The static load was applied in stages until the destruction of the prototypes. During the experimental researches, the displacements in the place of bending of the connecting elements of the prototypes were recorded. On the basis of the experimental data obtained, the values of compliance of the connecting elements of the vertical joint on embedded parts were determined. Correction coefficients for the correct definition the compliance of connecting elements in the form of rolled and bent angle bars of a vertical joint on embedded parts are calculated and proposed. A different nature of deformation and destruction of welded vertical joints on embedded parts with connecting elements in the form of rolled and bent angle bars with the same geometric dimensions under the action of tensile and shear forces on the joints is revealed.

The use of numerical models to analyze the behavior of steel elements has undeniable advantages and opens up a number of promising areas for the study of complex or new design solutions. The development of computer technology and software gives this direction a new stage of development - the use of numerical models in everyday design. For wider use of numerical models and ensuring comparability of results, it is important to develop universal principles for constructing numerical models with subsequent regulation in normative documents. Within the framework of this study, emphasis is placed on the use of numerical models on a par with classical (formula) models, and first of all, for this purpose, a review and systematization of the most important parameters of numerical models of load-bearing capacity is carried out. The instructions on the purpose of the properties of materials, the type of the final element, the quality of the mesh, the size and shape of imperfections applied to steel structures are presented. The results obtained are of interest for further research on the unification of the requirements for the parameters of numerical models and their verification based on experimental data with the calculation of statistical characteristics of the uncertainty of the numerical model.

The efficiency of the use of cross-corrugated beams can be increased by tilting the corrugations on the supporting sections of their walls. The paper presents the results of a study of the stress-strain state of steel I-beams with a thin inclined-corrugated wall, depending on the angle of inclination of the generatrix of the corrugations to the plane of the cross-section of the beam. The finite element models of beams with different inclination angles of the generating corrugations (corrugation profile triangular continuous open) are presented, as well as the results and a brief analysis of numerical experiments carried out using the software package LIRA-SAPR. In the course of the experiment, for each model, the forms of wall buckling with safety factors, deformed schemes and distribution isofields of normal, tangential and principal stresses in beam elements were obtained. The presented results indicate an additional increase in the stability of the wall with downward corrugations, a change in the forces in the chords of the beams, and a slight increase in their deformability.

The article presents an approach to structural reliability analysis based on interval estimates of random variables, which represent the boundaries of random variables’ variability. Numerical examples show that the use of such an approach in cases with nonlinear mathematical models of limit states allow to obtain a more cautious estimate of the failure probability with a decrease in the number of statistical hypotheses used. The proposed approach uses the Vysochanskij–Petunin inequality to justify the limits of variability of random variables without using hypotheses about the distribution shape of a random variable. The mathematical expectation and standard deviation are also represented by confidence intervals which increases the practical significance of the developed method. Algorithms for using the proposed approach are presented on numerical examples of estimates of the no-failure probability of structural elements.

The paper experimentally and theoretically considers the issues of assessing the robustness of reinforced concrete structural systems with flat slabs in an accidental design situation.

The methodolody of experimental studies for two scale models of a flat slab fragment in the case of removal of the central support under static (sample FS-1) and dynamic (sample FS-2) loading are presented. Based on the data obtained, the analysis of the main mechanisms of resistance of flat slabs to progressive collapse was carried out.

The article presents a theoretical approach to a direct quantitative assessment of robustness, which is based on the provisions of the energy balance of a damaged structural system in an accidental design situation. The proposed solutions make it possible to determine the non-linear quasi-static "loaddisplacement" reaction and the ultimate dynamic resistance for reinforced concrete structural systems with flat slabs in the case of removal of the vertical key element.

The article considers the various foundation design for different regions of the Russian Federation. The calculation of the pile foundation was carried out taking into account the peculiarities of hydrogeological conditions in these regions for the multifunctional sport complex. The spatial frame modeling was performed using SCAD and Autodesk AutoCAD software packages. According the calculation S-5-30 5 m long with a section of 300x300 mm (by series) piles received for the Republic of Bashkortostan. For the Republic of Tatarstan: piles according to the S-3-30 series, 3 m long, with a section of 300x300 mm. According to the S-6-50 series, 6 m long, with a section of 500x500 mm piles are accepted for the Perm Territory. To define the price of building foundations, a local estimate calculation was composed based on bills of quantities. Based on the presented final price, it can be concluded that different categories of engineering and geological conditions complexity, imply additional activities in areas with more complex hydrogeological conditions. The cost of building the foundation for the Republic of Bashkortostan amounted to 93.711 million rubles, and turned out to be the largest in comparison with other regions, which is associated with a significant increase in the volume of work due to the installation of monolithic reinforced concrete belts. The authors noted, that analysis of engineering and geological conditions of the construction site is the determining factor in the choice of foundation structures for the designed building. The presented methodology allows to carry out a similar industrial and public buildings feasibility study in construction not only in the considered regions but throughout the Russian Federation.

The main causes of the destruction of the front brick are considered. It is indicated that the properties of ceramic products during their operation in masonry largely depend on the quality of the preparation of the clay mass. Seasonal freezing of clay improves its molding and drying properties. The height of the cone during seasonal storage of clay for the climatic conditions of the Moscow region should be no more than 6 meters. It is confirmed by calculation. A critical analysis of the theory of chemical destruction of ceramic bricks during the interaction of alkalis with oxides of silicon and aluminum of the amorphous phase is presented. Calcium and magnesium ions have a much lesser effect on the corrosion processes of bricks because of the formation of easily soluble silicates and aluminates compared to sodium and potassium ions. It is proposed to separate the requirements for frost resistance of facing bricks is proposed depending on the climatic conditions of the construction.

The effects of structure formation in disperse systems obtained by pelletizing in the manufacture of asphalt concrete mixtures with the inclusion of up to 30% phosphogypsum have been considered. In studying the physical-chemical and consumer properties of bitumen with polyethylene terephthalate additive they used the method of measuring the wetting edge angle. Microphotographs of modified binder make it possible to judge about the change of bitumen surface state. Thermal effects occurring as a result of modifying properties of such materials were registered. It was found that production of asphalt-concrete mixture by pelletizing provides high indicators of compressive strength of the hardened material. We found an increase in asphalt concrete water resistance at simultaneous introduction of polyethylene terephthalate and industrial waste phosphogypsum powder into the disperse system. Synergetic effect of the above additives on the achievement of positive effect of structure formation in asphalt-binding materials has been revealed, which reveals new prospects for their use in the production of construction works.